In multimedia interface for which the needs has been sharply increased recently, a high speed and large capacity data transmission under various user circumstances, such as in public, office, home and the like, is desired. As one of multimedia interfaces which provide such high speed and large capacity data transmission, a high speed wireless access network, a high speed radio access network or the like is getting the focus of public interest.
As examples of typical structures of such networks, there are a master-slave type network and a direct link type network. In the master-slave type network, by means of a central control via a communication terminal holding apparatus, a plurality of terminal apparatus carry out communication with the communication terminal holding apparatus. On the other hand, in the direct link type network, by means of a central control via a communication terminal holding apparatus, which has the control right in one or more communication terminal holding apparatus, a plurality of terminal apparatus and other communication terminal holding apparatus carry out communications respectively.
A master-slave type network shown in FIG. 1 comprises a communication terminal holding apparatus 11 which has an access point (AP) facility equivalent to a base station apparatus in a mobile communication system, and MT device apparatus 12, 13 and 14 having a mobile terminal (MT) facility respectively, which is equivalent to mobile station apparatus of a portable telephone apparatus or the like. In the master-slave type network, the communication terminal holding apparatus 11 carries out a scheduling in which communication resources such as time area and frequency or the like are assigned, and the communications between the MT device apparatus is made by surely being interposed by the communication terminal holding apparatus 11. For example, in a case where the MT device apparatus 12 carries out a communication with the MT device apparatus 14, the MT device apparatus 12 transmits a signal to the communication terminal holding apparatus 11 in accordance with the scheduling by the communication terminal holding apparatus 11.
A direct link type network shown in FIG. 2 comprises CC/WT device apparatus 21 and 22, which have a central controller (CC) facility and a wireless terminal (WT) facility, and WT device apparatus 23 and 24, which have a WT facility only, and communication is made directly between the WT device apparatus. Herein, the control right is transferred periodically between the CC/WT device apparatus 21 and 22, which have the CC facility respectively, and the apparatus having the control right carries out the scheduling. For example, when the CC/WT device apparatus 22 makes a request for a communication with the WT device apparatus 24 at a point of time when the CC/WT device apparatus 21 has the control right, the CC/WT device apparatus 21 carries out the scheduling in which communications resources such as time area and frequency or the like are assigned.
Since each MT device apparatus carries out data communication only to the communication terminal holding apparatus, the master-slave type network has such merit that the MT device apparatus has a simple structure. On the other hand, since the data communication is carried out directly between the WT device apparatus without being interposed by any other apparatus, the direct link type network has such a merit that the communication resources can be utilized effectively.
As the field of the network application expands, such needs that the MT device apparatus used in the master-slave type network is desired to use also in the direct link type network are raised. As one of the methods to meet the needs, such a method that, as shown in FIG. 3, a terminal apparatus 31, in which a WT facility is added to a MT facility is introduced, has been proposed conventionally.
However, in this method, such problems reside therein, i.e., an MT device, which is conventionally used, can not be used as it is and the size of the terminal apparatus becomes larger resulting in elimination of the merits of the master-slave type network. Also another problem such that MT device apparatus (MT device apparatus 13, 14 in FIG. 3), which are not provided with the MT facility, can not be used in a direct link type network resides in.